问题 B: 复制字符串

#include<stdio.h>
void strcpypos(char s2[],char s1[],int pos)
{
int i,j=0;
for(i=pos-1; s1[i]!='\0'; i++,j++)
{
s2[j]=s1[i];
}
s2[j]='\0';
}
int main()
{
char s1[256],s2[256];
int n,pos,i;
scanf("%d",&n);
getchar();
for(i=0;i<n;i++)
scanf("%c",&s1[i]);
s1
='\0';
scanf("%d",&pos);
strcpypos(s2,s1,pos);
printf("%s\n",s2);
return 0;
}